(CBS News) In impassioned remarks at Tuesday's Republican National Convention, former Republican presidential candidate Rick Santorum called on Americans to elect Mitt Romney as president in order to stop what he cast as an "assault on marriage and family."

Santorum, speaking during the event's opening night, blasted President Obama for pushing policies he argued "undermine the traditional family," and have subsequently resulted in a failing national educational system.

"The fact is that marriage is disappearing in places where government dependency is highest. Most single mothers do heroic work and an amazing job raising their children, but if America is going to succeed, we must stop the assault on marriage and the family," he said. "Under President Obama, the dream of freedom and opportunity has become a nightmare of dependency with almost half of America receiving some government benefit."

The former Pennsylvania Senator offered up his formula for economic success: Work hard, go to school, and get married before having children.

"In America we believe in freedom and the responsibility that comes with it to work hard to make that dream of reaching our God-given potential come true," he said. "Graduate from high school, work hard, and get married before you have children and the chance you will ever be in poverty is just two percent."

Voting for Romney, Santorum assured voters, "will put our country back in the hands of leaders who understand what America can and, for the sake of our children, must be to keep the dream alive."

"I thank God that America still has one party that reaches out their hands in love to lift up all of God's children - born and unborn - and we say and we say that each of us has dignity and all of us have the right to live the American Dream. And we also say that without you America is not keeping faith with its dream," he said. "That all men all men are created equal and endowed by their creator with the right to life, liberty and the pursuit of happiness."

In remarks following Santorum, Ted Cruz, a rising Tea Party star and Texas Senate candidate, reiterated the notion that Romney, not Mr. Obama, will enable voters to continue in pursuit of the American dream.

Cruz, who is of Irish, Italian and Cuban descent, attributed his beliefs in part to lessons learned from his father, who he said was imprisoned and tortured in Cuba before escaping to Texas.

"He had nothing, but he had heart. A heart for freedom," Cruz said. "It's the story of each and every one of you. We are all sons and daughters of those who risked everything for freedom, and we have the duty to pass that same opportunity to the generations to follow."

Like Santorum, he blasted Mr. Obama for "destroying individual responsibility." He also accused him of "attempting to "scare" Americans and preach a message of "division."

"Unfortunately, President Obama's campaign is going to try to divide America," he said. "They're going to try to separate us into little groups, and try to scare everybody. They're going to tell seniors that Medicare will be taken away, tell Hispanics that we're not welcome here and send the Vice President to preach a message of division."

Artur Davis, a Democrat-turned-Republican former congressman, meanwhile, said he was correcting the "mistake" he made in 2012 - when he not only supported Mr. Obama, but actually seconded his nomination during the 2008 Democratic convention.

"America is a land of second chances, and I gather you have room for the estimated 6 million of us who know we got it wrong in 2008 and who want to fix it," he said, of his past support for the president. "Do you know why so many of us believed? We led with our hearts and our dreams that we could be more inclusive than America had ever been, and no candidate had ever spoken so beautifully."

But, he said, "So many of those high-flown words have faded."

"There are Americans who voted for the president, but who are searching right now, because they know that their votes didn't build the country they wanted," he said. "To those Democrats and independents whose minds are open to argument: listen closely to the Democratic Party that will gather in Charlotte and ask yourself if you ever hear your voice in the clamor."

Davis said he hoped to help correct the "mistake" he had made in 2008 by helping to elect Mr. Obama.

"May it be said of this time in our history: 2008 to 2011 - lesson learned," he said. 2012: mistake corrected."

Davis is not the only person at the 2012 conventions representing a party he once ran against: Former Governor Charlie Crist, R-Fla., who now identifies as an independent, recently endorsed President Obama and will speak next week at the Democratic convention in Charlotte. It's not a move lacking in historical precedent: In 2004, Democratic Senator Zell Miller of Georgia was so disenchanted with his party that he endorsed President George W. Bush and spoke at the Republican National Convention without even bothering to switch parties.